(a) Field of the invention:
The present invention relates to an electronic musical instrument having an automatic accompaniment device which, in one aspect, is capable of automatically performing an accompaniment of a pattern custom-made or programmed by the user, and in another aspect, capable of automatically producing a so-called rhythmic chord accompaniment by beating those chord tones inputted by the user's manipulation of the keyboard with a desired rhythm.
(b) Description of the prior art:
In the past, there has been known an automatic accompaniment device for use in an electronic musical instrument arranged so that an accompaniment pattern such as arpeggio or arpeggic chord (which is an arpeggio of a plurality of simultaneously produced tones) of a normalized pitch format which is stored in a ROM (Read-Only Memory) is subjected to, for example, a tonality shifting in accordance with the chord information inputted by the user's manipulation of keys on the keyboard to thereby alter the tone pitches into absolute tone pitches for being sounded out as an automatic accompaniment. Such an automatic accompaniment as effected in the prior art, however, is nothing but a mere automatic reproduction of factory-made accompaniment patterns which have been stored in advance in a memory means of the device, and accordingly it has not necessarily given satisfaction to the user.
Also, as a rhythmic chord accompaniment device of the prior art for use in an electronic musical instrument, there is the one which performs a conventional auto-bass-chord (ABC), and the one which performs an automatic accompaniment by using a chord sequencer based on stepwisely inputted chords. It should be noted, however, that the rhythmic chord accompaniment device which plays auto- bass-chords has the inconvenience that the accompaniment performance is scarce in variation and lacks the tint of one's tastes or liking because, as stated above, such an accompaniment is only the reproduction of the preliminarily memorized pattern. The chord sequencer, on the other hand, is a device designed to input informations of tone pitches and note durations stepwisely. Thus, this latter device is of such disadvantages that the player (user) is unable to quickly catch or grasp the actual performance, and this in turn gives the player a difficulty in making a subtle controlling of timing for key depressions and key releases.